Flying machine



F. BURRELL FLYING EJIACEINE Filed 192.3 2 Sheets-Sheet E. F. BURRiLLPLYENG v fin BIACEHEH File-i Aug. 16, 2 Sheets-Sheet 2 Patented Mar. 17,1925.

ELVYN FREMONT BURRILL, 0F BERKELEY, CALIFORNIA.

FLYING MACHINE.

Application filed August 10, 1923. Serial No. 656,627.

To all whom it may concern:

Be it known that I, ELVYN FREMONT BUR- KILL, a citizen of the UnitedStates, residing at Berkeley, in the county of Alameda and State ofCalifornia, have invented a newpower of varying the magnitude of thever-' tical,'or lifting thrust, by small degrees so as thereby to varythe rising or falling speed at will, and to attain stationary, orhovering flight.

The mechanisms combining in a machine of this character fall naturallyinto three groups: '(1) the fundamental, or lifting and drivingmechanism; (2), the voluntary controls for effecting rising, falling,and hovering, and for" changing from vertical to horizontal flight andvice versa; (3), the automatic safety devices for easing the machine tothe ground in case of failure of the power.

The principal object of the present invention is to provide a flyingmachine of the highest possible flexibility, universal in itsdirectional capacity, adapted to carry a single flyer and suflicientlysmall and light to be responsive in its directional controls to leaningsor small sliding movements of the" pilots body, so that it might notinaptly be called a powered flying bicycle.

A. further object is to work intrinsically into the structure thehighest degree of safety possible without resorting to separate andweight producing devicesfor that purpose.

It is well understood thatv the main reason for the small progress asyet made in this field is the lackof' a. propelling mecha nism ofadequate power andfefiiciency. Ac-,

cordingly it' is my central and mostimp'or tant object to provide suchadequate propel ling mechanism.

So formidable, however, are the inherent difiiculties of vertical flightand so different from those involved in flight as at present developed,that vertical flight is as yet a new and practically unknown art.Furthermore, on'a'ccount of the absence hitherto of any scientificstatement of these difliculties and of the principles involved, andsince they are inseparably connected with and must dictate theaerodynamic character of any mechanism designed for their solution, itwill be proper to explain, in a general way, the fundamental difficultybefore proceeding to the specific mechanism.

In the case of the aeroplane, the propeller is called upon to performbut one twentieth to one tenth of the total work of sustaining the planein the air, While in a machine for vertical flight the propeller mustperform the total work of sustentation; Thus it is seen that howeveradmirable the aeroplane propeller is for its purpose, it is essentiallya ight duty instrument. f

Given an aeroplane requiring a fifty horse power engine and propellerjust to sustain it in level flight; to lift the same plane verticallywould require an engine and propeller,

if of the same form, of five hundred horse power, and this withoutcounting the greatly'increased weight of the engine and pro peller. Toovercome this increased weight, a still further augmentation of thepower would be necessary, and so there ensues a critical race betweenthe ever increasing weight and the increased power necessary to overcomeit.

Thus it is evident that mere lightness becomes .a prime object and ofthe essence of the invention, and this must be accompanied by suchaerodynamic power andefficiency as only the most rigorous attention toeconomy can evolve. Consequently all the elements entering -1nto mymachine contribute to these two objects, in-order that it may be able tolifting perform its basic function, namely, its load.

,There exists but one general type of mechrotational velocity remainsconstant and the dimensions aregincreased proportionally, the

generated aerodynamic power increases as the fourth power of. the,dimensions while the weight increases only as; the cube of, the

loo

dimensions; so that as the dimensions are increased the lifting poweroutruns the wei ht. One form .of symmetrical or dou le turbinaero isembodied in a patent issued to me Nov. 15, 1921, Patent No. 1,397,400;and the present invention involves the same instrument in a modifiedform.

The general arrangement and effect ofthis mechanism may be bestunderstood by reference to the skeleton Fig. 7 accompanyin which ismerely a conventional figure or explanatory purposes, and may beregarded as a cross section of an imaginary apparatus. In Fig. 7 a, b,0, d, represent the vanes of a pair of tangential fans, rotating in thevertical plane in opposition. as indicated by the arrows. These fanswhen rotating uncovered in the open angenerate an aerodynamicpower inthe form of an infinitude of tangential force lines equally dispersedall aroundthe peripherice, and the coordinate sum of these forcelines-is, of course, zero. By a well known mechanical principle,corresponding" reactions take place about'the fan pivots and the sum ofthese reactions is also zero. Assumi ng the vanes to be flat or nearlyso and the force lines strictly tangential, since the vanes strikeftheair with an angle of incidence of 90, the quantity or magnitude ofaerodynamic power per unit area is the greatest ible to the science; andconversely, t e area and therefore the weight per dynamic unit is thesmallest possible. Now when the directors or guide planes PP,

' and PP are placed in relation to the fans as shown, the dispersedcircular and therefore neutralized force lines are collected andcombined in their totality into a solid vertical dynamic, the downwardthrusts, or actions, 1mpinging on the stationary air, and

the reactions forming an upward thrust under the crowns of the planes.While this takes place, the reactions about the pivots remain algebraiczero, so that there are no hostile or downward thrustscommunicated tothe mechanism through the pivots, and there results a net lift equal tothe total generated aerodynamic power. Since as stated above thegenerated dynamic is the greatest possible, it follows that theresulting lift is also the greatest possible per unit upon the turningangle. If such turning angle is the direction of the imparted motiveforce isat right angle to the original direction of the stream, and itsamount is unity, that is, equal to the total force residing in thestream. If the turning angle is 180, so that the stream is turnedcompletely back upon itself, the imparted motive force is in line withthe direction of the stream, and its amount is double the'force residingin the stream.

Reverting now to the Fig. 7, it will be seen that the aerodynamic streamhaving its initial point at vane a, is turned by the concave P back uponitself, or through 180, and therefore impresses a lift under the planedouble its own initial force. The stream having its initial point atvane b is turned 90, thus impressing a lift under the plane equal to itsown inherent force. Vane 0 receives a unity lift of reaction directlyupon itself which is communicated to the mechanism through the pivots.The stream with initial point at vane cl is received by plane Pandlturned downward 90, thus impressing unit lift under that plane. It.can be demonstrated both mathematically and-experimentally that the liftof this system is substantially equal tothe total generated aerodynamicpower.

Having thus laid the ground of basic principles, my apparatus will beunderstood as a whole and in detail by reference to the accompanyingdrawings, in which: Fig. 1 is a side view of the double turbinacro, showing a vane of the purely tangential fan, in which case the vane isstraight.

Fig. 2 is a rear end View with fuselage removed showing the internal.and general structure.

Fig. 3 is a side view showing the slightly helical vanes and with aportion of the upper guide plane broken away to show posi tion of pilotsseat whenslightly rearward of the center and machine careened rearwardlya few degrees in the attitude of purely .vert-ical flight.

Fig. 4 is a side View showing pilots seat in central position and themechanism on level keel in attitude of horizontal flight.

Fig. 5 is a top or plan view with planes removed showing organization ofthe power and transmission system.

Fig. 6 is a detail of the engine sheave showing the method of ratchetand paw] engagement with the engine spindle.

Fig. 7 is al-'diagrammatic sectional view showing the directions of aircurrents in op eration.

Referring'first to the supporting member, 1, Fig. 2, is the base whichis the chief stiffening member of the whole system, and carrice theengines. It is preferably built in a box-like form of light plyconstruction.

Somewhat above the base at either end and fixed-to it'by uprightsupporting struts are lateral spars, 2,'reinforced by the curved braces3, the whole forming an approximately triangulated bracing system. Sincethe direction of flight is transverse of thesespars, they arestreamlined in cross section.

Upon these spars, at suitable distances from their ends, are fixedclamps 4., for holding the ends of tubes 5, which extend lengthwisethrough the center of the fan axles 6,-

and upon which they turn. These tubes also serve as fixed struts orspacers for the spars,

and since they are subject only to small linear strains, may be verythin and light.

At the ends of the tubes, just inside the clamps, where are located thebearings of the fan axes, the tubes may be reinforced with solid cores.Upon the tubes are mount edthe long fan axes 6. These are hollow and ofconsiderable diameter to resist the large torsional strains. They arebuilt up of .successive layers of ply wood so as to be very strong andlight. At their ends are in-' -serted hard wood disks bored out in thecenter to receive thebearings which turn on the tubes above described.

.their length, are fixed radial arms 7. for

supporting the vanes 8 of the fans. These may be light wood trusses,each comprising a pair of thin strips coupled together in parallel attheir ends and spread in the middle to embrace the large axes The vanes8, which may be as many as found most suitable, (four are here shown),may be made of wood veneers, duraluminum or other suitable material. Thevanes are parted midway of their length to provide space for the drivingsheaves and clearance for the cables.

Above and about the fans are mounted the cylindroidal directors or guideplanes 10, Figs. 1 and 2, upon whose under surfaces isimpressed theaerodynamic power generated by the fans. These planes are preferablymade of thin duralum inum'and may be supported in position in anyapproved manner, as by light wood curved trusses, not necessary tofurther describe. It isimportant, however, to give careful attention tothe curves in order to secure the highest dynamic ,ing vanes, of thefans.

efficiency. This is especially'true of the curvatures at the enteringand'trailing edges in reference to the air streams. Since the magnitudeof the thrusts due to impact and reaction under the crowns of the-planesdepends upon the volume and velocity of the air streams, it is necessaryto make the entering curvature such that the streams may impinge with aglancing blow and so be eased'into the concave without injury to theirvelocities. are presented conditions similar to those at the sternofajyacht, where the lines must be so designed as to prevent draggingswirls and to secure a clean parting of the water from the curvedsurfaces. So in the present case, after the entering streams have beenturned through a full 180, and issue downward from under the-planes,these should depart'by slight degrees, in the latter portion of theircurve, from true circularity so At the trailing edges there as to securea gradual parting with the fall-- I curve is circular and may beas closeto the path of the vane tips as consistent with safe clearance. The.planes should be polished For the rest the on their under surfaces toreduce air fric tion. I

Through the lower arc of rotation it is manifest that the tangentialforce lines are spread out fanwise and exert a lifting effect byreaction under the vanes until the vanes in succession approach thelower vertical position, when the" tangents approach the horizontal andso lose their lifting effect. In order to utilize these lowerhorizontally tending force lines and to turn them downward, the planes11, 11 are provided. Throu h the turnin reaction of these lines a liftis exerted under these planes. In all these operations the air enters atthe vacant core and is thrown outward by centrifugal force w theperipheries I Planes 11, 11, in addition to performing approximately onefourth of the totallift,

also perform another very important function. On account of the greatflexibility designed in the resent machine, it becomes necessary to enow it with a wider range of variability of lift than heretoforeprovided, the reason for which will appear later in the specification.These planes are hinged along their upper edges so as to be swunmanually in and out as shown by the soli 1 lines and dotted lines,'in Fi2, indicating their varying positions. T e manner in which theyaccomplish the variability'of lift is as follows: Whenthe planes areretired to their extreme positions back to back as shown' by the solidlines, they contribute their maximum quota to the lift; when they aregradually opened outward the lift is diminished because the. forceslines strike them with a head-on collision as shown by cluding zerolift, to a considerable deprcs-.

sion on the negative side. The requisite movements are accomplished bymeans of a hand control wheel 22 on the pilot's control board, similarto the steering wheel of an automobile, which operates a' system ofcables attached to theplanes, all of which control system is well knownand needs no further description.

The specification thus far has dealt with the strictly aerodynamicelements of my invention. Since this form of lifting and fiyingmechanism is a pioneer in the field of aviatics, nothitherto known orused, I do not limit myself to the precise ,forms and mechanisms hereindescribed, but reserve freedom to employ other means provided theyaccomplish the same results. For instance in the case of planes 11, 11,just described, it is evident that they might be'fixed: at their loweredges while their upper edges swing downward. In such case as their up-"per edges pro ressed downward they would cease toturn t e air streamsfromthe lower inward striking vane downward, and said streams would iminge upon their tops, and

so substantially t e same results would be accomplished as thatindicated'in the draw- 1ngs.-

This principle holds also in regard to the shape of the fan vanes. InFig. 1 I have shown the vanes as straight while Figs. 3. and 4; showthem having a slight helical curve. If I make the vanes straight so thatthe force lines are strictly tangential,- the machine' is still avertical flying machine and I am privile ed to employ any of thehorizontal prope lers now in use to drive it for- Ward after it hasrisen into the air under its vertical propellers.

ButIprefer, for the sake of simplicity and lightness, to incorporate anaxial thrust intrinsically in thefans. This I do by giving the vanes aslight helical. curve similar to the blades of a lawn mower, as shown inFigs. 3 and 4, since the direction of flight is axial to the fans' Thedegree of the helical curve is such that only a minor component of thetotal thrust is diverted to hor zontal propulsion, since the majorthrust must always be reserved for the far heavier work of sustentation.

Coming now to the directional controls,

these involve the manner of securing rising,

falling and hovering, and changing from vertical fli'ht. to horizontaland Vice versa. To accompish these results, I place the pilot upon asliding seat, 22, mounted sl idably upon the runners 23, in a manner smilar to the seat of a racing shell. The small foreand-aft movement ofthe seat along the runners is controlled by a pedal operating a sprocketgear of a well known character which needs no special descri tion. Bythis means the center of gravity 1s moved longi-' tudinally and themechanism is thereby cause-d to careen slightly backward, or to rest oneven keel, according. as the pilot slides a few inches in eitherdirection along the runners, or occupies a central position.

Assuming now wings 11', 11 to be retracted to their extreme inwardposition, back to back, and the machine consequently exerting itsmaximum lift, since there are both axial and tangential thrusts, it isclear that the direction of flight will be obliquely upward, providedthe pilot occupiesthe central'position and the machine is on level kecl.It 'now the pilot wishes to secure "purely vertical flight, he slides afew inches backward along the runners, when the mechanism will assumethe attitude shown in Fig. 3. It is seen that in this attitude the axialthrust is directed slightly upward of the horizontal as shown by theaxial arrow. The circular, or lifting thrust, is at the same timeinclined slightly backward of the vertical as shown by the rearward ofthe two upward pointing arrows, Fig. 3. Both of these eflects'conspireto set up a resistance to forward movement and to producea purelyvertical resultant. shown by the strictly vertical arrow. When the pilothas attained'his-desil'ed altitude he returns to the central positionand the mechanism returns to even keel when the axial thrust becomesstrictly horizontal as shown in Fig.

4, and there will be'forward movement. If

the pilot wishes to secure purely horizontal flight, he will graduallyreduce the lift by opening out wings 11, 11 until the lift just balancesgravity when the movement will be purely horizontal. It is' well knownthat a body moving horizontally weighs less than when stationary, asmanifested by the vertically downward pull, and the greater thehorizontal velocity the less the weight. In consequence of this fact themachine will have a tendency to climb as it gets up forward speed. Thismay be counteracted by opening wings 11, 11 more and more as speed isincreased, and thus an even altitude may be maintained. Conversely, whenthe forward speed is lessened wings 11,11

must be gradually retracted to prevent loss "of altitude. .It 'will thusbe evident that wings 11, 11' provide a sufficient variability of liftfor most purposes and above all they provide a sufiiciently, preciseadjustment of the liftvto attain an exact balancing of grav-' ity whichis necessary to secure a stationary or leanings of the pilots body. Thuswhen that is,'one pound per horse power.

basis the saving in engine weight'alone pro- I shall now show how .typeof engine in my double turbinaero to produce a vertical flying machineof hitheror hovering condition of the mechanism. When a large or suddenchange of lift is desired in order to secure a quick climb or descent,this may be attained by manipulating the engine speed, though thismethod is the pilot wishes to' swerve to the right or left of thestraight course, he needs only to lean to the right or left, whichmovement will displace the center of gravitylaterally and cause themachine to careen to one side thus introducing a lateral thrust when themachine will swerve to that side to which the pilot leans. a

But whatever care one might take to secure extreme lightness in theaerodynamic elements, it would be futile if he were limited to the enine s generally in use in aeroplane flight. ust as aeroplane flight hadto await the development of an engine of sufficient lightness andefficiency, so vertical flight has awaited still further refinements inthese directions. The majority of the engines now in use, weighing fromthree to six or more pounds per horse power, can' develop an aerodynamicpower scarcely more than suificient to lift themselves and the externalmechanism without useful load. There exists, however, a type of engine,recently developed, which is of so vital importance to the whole art ofvertical flight, and so highly adapted to my present purposes that abrief account of its basic characteristics is required. This is thedouble rot'ar type, as yet little known, in which radia 1y disposedcylinders rotate in one direction and the crank shaft in the oppositedirection; The efi'ective speed is the sum of thesetwo speeds. Thereresults a high engine speed, which means hi h power, attended with onlymoderate a solute speeds of the rotating elements. This fact allows theengine to be constructed with far thinner sections and of lightermaterials than is possible with other types. It has been proven feasibleto produce an engine of moderate capacity. with a weight-power ratio ofuniltly, -t is vides a suflicient lifting margin for my purposes. p

I incorporate this to unattainable lightness and, at the same time ofthe highest safety. A pair of engines, 12, Fig. 5, are mounted head tohead, centrally of the base, or fusela and. at the structural center ofthe tota mechanism, I

inent with the fan sheaves.

having the sheaves 13, 16 fixed upon their respective and oppositelyrotating cylinder cases and turning normally as a unit with them: andsheaves 14:, 15 mounted upon their respective and oppositely rotatingcrank spindles, and normally rotating with them; an exception will benotedlater in connection with the manner of their engage- Thus it isseen that the four engine sheaves 13, 14, 15, 16, rotate in alternateopposition, and with as close clearance as possible. This arrangementcauses the center of gravity to coincide with the structural center andneutralizes gyroscopic effects, thus securing good balance and easyturning control in the horizontal plane.

'Thc engine sheaves are engaged with the fan sheaves by means of twoendless cables, which are preferably thin woven linen cords, which arewound alternately over the grooves of the engine sheaves and fan sheavesin the followin manner: Beginning at an outer groove of an sheave 9,shown as the lowest one in Fig. 5, and at the bot tom, the cord isbrought up around the outer sector to the top; the cord passes thence tothe outer groove, beneath engine sheave 16, thence around to the top' ofthe sheave, thence to the second groove beneath fan sheave 9", thence uparound the sheave and again to the second groove beneath engine sheave16, and thus around and around'in a s iraloid winding until all thegroovesof s eave 16 are filled and one half the grooves of sheave 9. Thecord is now at the top of sheave 9, thence it passes directly to theouter groove beneath fan sheave 9 as shown in Fig. 2. The cord isbrought up around sheave 9", thence to'the'first groove beneath" end atthe bottom of sheave 9 and the endat the top of sheave 9", are broughtdown and spliced around the automatic take-up pulleys 12, which serve toalign the last strand from the staggered first halves of sheaves 9 and9", and to e%ualiz e the ten- 7 sion on all the strands. T ewindings ofthe other and entirely separate cord around the other halves of sheaves9 and'9", and engine sheaves 13 and 14, are precisely similar but intheopposite direction, that is beginning at the outer grooves andproceedmg inward.

have illustrated but one of several les of winding 'the drivingcablewhichmight be employed. Three 'un 'rtant results aecrue' from thissystem0 drive and trans mission. It will be noted that the winding results ina web of strands inter-crossing begine sheaves. It will be further notedthat both engines participate equally in the drive of both fans, thesignificance of which in relation to the problem of safety willpresently appear. In this connection it becomes necessary to revert morespecifically to the -mountings of the engine sheaves upon theirrespective s indles and sleeves; The sheaves are not in exibly fixedupon the spindles, but" the method of mounting will be made clear byreference to the detail Fig. 6. In the figure 16* is a sleeve castintegrally upon the cylinder case and turning upon the crank spindle15?. Upon this sleeve and against the face of the cylinder case is likeda ratchet wheel 17. Against the ratchet wheel and upon the'sleeve 16 ismounted the sheave 16 which isprovided with pawls 18 engaging theratchet wheel 17, so thatsheave 16 is forced to turn as one withthe'cylinder case.

Upon spindle 15, which extends beyond the end of the above describedsleeve, is fixed a similar ratchet wheel, and adjacent to this ismounted sheave 15, also provided with pawls engaging the ratchet wheel,and so forced to turn under the drive of the crank spindle 15. Theremaining pair of sheaves is mounted in a precisely similar manner onthe sleeve and spindle of the other engine. I contemplate engines 20flarge reserve power so that in an emergency either engine could nearlysustain the'mechanism alone.

Now in case one of the engines shouldbecome stalled, the live enginewill automatically assume the entire load, the sheaves upon the deadengine will be automatically released and free to turn as idlers uponthe sleeve of the cylindercase and s indle of the crank shaft, and thestalledlengine will thus be automatically cut out of'the system. Underthese conditions the machine will settle gently to the ground. It is tobe further noted that the mechanism'is a natural para chute and withboth engines dead it still would fall in an upright attitude and withvelocity so retarded as not to be disastrous.

'Thecombination of these two features provides a factor of safety nothitherto realized. In face-since the center of gravity lies considerablybelow the chief points of support, namely, under the crowns of planes10, the mechanism possesses inherent stability and whether risin orfalling will always main- 1 approved character and need not be furtherdescribed. If desired, pontoons could be provided for alighting onwater.

The mechanism having now been fully described, the method of operationis as follows: The machine standing upon its supports, the pilot openswings 11 to their extreme outward positions. He then primes the enginesand turns the throttle to low speed. Standing at one corner of themachine he grasps an outer radial arm of one of the fans and gives it asmart downward thrust, whereupon the engines start. He then mounts hisseat and speeds up the engines. When these are sufficiently warmed upand he is ready to rise, he turns the control wheel retracting wings 11to their extreme inward position when the machine will rise. Should hewish to rise vertically, he slides backward a few inches when themechanism will take the attitude shown in Fig. 3 and the upward movementwill be purely vertical. When a sufficient altitude has been reached thepilot slides forward to a central position and the mechanism will beginto move forward. As the machine accelerates horizontally, wings 11 mustbe gradually opened out to prevent climbing. Should the pilot wish tosecure a hovering position over an objective, as for taking photo raphsof some object on the ground,

he sli es backward slightly, thus introduc- -inga resistance to forwardmotion, at the same time retracting wings 11 in order to maintainaltitude, when by nice adjustments the machine may be brought to astationary or hovering condition. When the pilot is ready to descend, ifthe altitude is consider- .able', he will open wings 11 to their extremelimit when he will fall rapidly, until he approaches the ground when hemust retract wings 11 thus causing the machine 1: slow down andas henears his objectiv he may secure any degree of slowness until entlyalights with little or no shock.

fining now elucidated my invention as to its principles, constructionand use, what Iclaim is: i

1. In a flying machine, in combination with a air of vertically andoppositely'rotating ans, or generators of aerodynamic IOU power, andcylindroidal directors, or guides planes placed above and aboutsaidfans, adapted to collect the tangentially dispersed air streams aboutthe peripheries of the fans throughout the lower-inner and upper-innerquadrants, and to turn said streams downward; rigid cylindroidal guideplaced below and inwardly of the fans, adapted to collect the dispersedlower-hori zontally tending air streams from the lower arcs of rotationand to turn said streams downward, substantially as specified.

2. In a flying machine, in combination with a pair of vertically andoppositely ro-I tating fans, and cylindroidal guide planes placed aboveand about said fans, adapted to collect the tangentially dispersed. airstreams about the inner portion of the peripheries of the'fans and toturn said streams downward; rigid cylindroidal guide planes placed belowand inwardly of the fans, adapted to collect the lower-horizontallytending air streams from the lower arcs of rotation and to-turn saidstreams downward; said lower guide planes bein swingable manually inwardand outwar as and for the purpose specified.

3. In a flying machine, a turbinaero comprising a pair of vertically andoppositely rotating fans; cylindroidal uide planes placed above andabout the ans, adapted to collect the upward tending and upperhorizontally tending air streamsfrom'the inner portions of theperipheries of the fans and to turn said streams downward; and rigidcylindroidal guide planes placed below and inward of the fans, adaptedto collect the lower-horizontally tending air streams from the lowerarcs of rotation and to turn said streams downward, substantially asspecified.

4. In a flying machine, in combination with a )air of vertically andoppositely rotating ans, the vanes of said fanshavin'g a helicalcurve;cylindroidal guide planes placed above and about the fans; andcylindroidal guide planes placed below and inward of the fans, saidlower guide planes being swingable manually inward and outward; a pilotsseat movably mounted on fore-and-aft runways, said pilots seat beingcontrollable as to its fore-and-aft posi tion along the runways.

5. In a flying machine, in combination with a pair of vertically andoppositely rotating fans, said fans being provided with sheaves, a powerplant comprising a pair of double rotary engines, set head to head,having their axes aligned fore-and-aft of the mechanism, the fourspindles of said engines having mounted upon them four driving sheavesrotating in close proximity and in alternate opposition, and drivingmeans conmeeting said fan sheaves and driving sheaves.

6. In a flying machine, in combination planes with a pair of opposedvertically rotating fans anda corresponding pair of double rotaryengines, said fans and the spindles of said engines being provided withgrooved sheaves,a transmission winding comprising.-

endless cords wound in spiraloid formation around the grooves of the fansheaves and engine sheaves, engaging both engines equally withv bothfans, and forming webs of strands intercrossing between the enginesheaves and fan sheaves.

7. In a flying machine, in combination with a pair of opposed verticallyrotating fans and a pair of double rotary engines, sheaves on the fanaxes and on the engine spindles, the combination ofendless driving cordswound in spiraloid formation around the fan sheaves and engine sheaves,engaging both engines equally with both fans and forming webs of strandsintercrossing between the engine sheaves and fansheaves, and means forautomatically regulating and equalizing the tension on all the strands.

8. In a flying machine, in combination with a pair of opposed verticallyrotating fans and a pair of engines, fixed sheaves on the fan axes,loose sheaves on the engine spindles, endless transmission cords woundin spiraloid formation around the fan sheaves and engine sheaves,engaging both engines equally with both fans, and automatic tensionregulators; means for engaging the engine sheaves with their spindlesand for automatically disengaging the sheaves of either engine andcausing them to rotate as idlers upon their spindles.

9. In a universal flying machine, a vertical flying machine, comprising,in combination, a pair of vertically and oppositely rotating fans;cylindroidal guide planes placed above and about the fans; 0 lindroidalguide planes placed below an inward of the fans, said lower guide planesbeing swingable manually inward and outward; a pair of double rotaryengines; fixed sheaves on the fan axes, loose sheaves'on the enginespindles: endless driving cords wound in spiraloid formation around thefan sheaves and engine sheaves engaging both engines equally with bothfans; automatic tension regulators; and means for engaging the enginesheaves with their spindles and for automatically disengaging thesheaves of either engine and causing them to rotate as idlers upon theirspindles.

10. A universal flying machine, comprising, in combination, a pair ofvertically and oppositely rotating fans, the vanes of said fans-having ahelical curve; cylindroidal guide planes laced abovev and about saidfans; cylindroidal guide planes placed below and inward of the fans,said lower guide planes being swingable manually inward and outward; apilots sea-t movably mounted on fore-and-aft runways, said pilots seatbeing controllabl'e as to its osition along the runways; a pair of don1e rotary engines; fixed sheaves'on the fan axes, loose sheaves on 'theengme spindles; endless dIlV- fans; automatie tension regulators; andmeans for engagin'g'th'e engine sheaves with their spindles and forautomatically disen- 1 gaging the sheaves of "either engine and. causingthem to rotate as idlers upon their spindles, substantially as secified, ELVYN FREMON BURRILL.

